This invention relates to spectacle lenses, and more particularly to an improved method for grinding the edges of such lenses to form thereon intersecting beveled edges which have extremely sharp corners or facets.
It has become fashionable to wear spectacle frames which are attached only to their associated lenses at spaced points. In other words, instead of extending completely around and enclosing outer, marginal edges of each lens, the frame is fastened to each lens at only a few points. The purpose, of course, is to leave substantial portions of the outer peripheral surace of each lens exposed. This permits the exposed edges of the lenses to be ground in various configurations designed to flatter or embellish the facial features of the person wearing the spectacles.
Spectacles of this type that have become particularly popular are those using lenses which have substantial portions of their forward edges beveled. Even more popular are the lenses which have been ground to form along their upper edges of plurality of intersecting, beveled surfaces. Most desirably these points of intersection of the beveled surfaces form sharp corners, which therefore provide the appearance of the facets of a gem.
Unfortunately, however, it has been extremely difficult and expensive to form the desirably sharp corners between intersecting beveled edges on multifaceted lenses of the type described. Heretofore it has been the practice to grind the intersecting, beveled edges on the upper end of a lens in a single operation, and the result has been the formation of a rather rounded corner at the intersection of adjacent surfaces. The two surfaces must then be hand ground to remove from each a quantity of glass or plastic sufficient to generate between them a sharp, well-defined edge or corner. Because of the time and labor involved in forming such sharp corners, these multifaceted lenses heretofore have been extremely expensive to produce.
It is an object of this invention, therefore, to provide an improved method and means which considerably reduce the cost of producing sharp-cornered, multifacted spectacle lenses of the type described.
Another object of this invention is to provide an improved method of the type described which eliminates the need for manual operations in producing multifaceted lenses for spectacle frames.
Still another object of this invention is to provide an improved series of lens formers which permit the rapid and accurate grinding of intersecting beveled edges on lens blanks of the type described, and in such manner that the intersections are defined by extremely sharp corners.
Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings.